You are right that details are not out. What I said was purely conjecture on the part of WP8. However, given the roadmap, rumors, hints, discussions, the kind of people in charge (Sinofsky, known .Net hater), etc... I am pretty sure that WP8 will be like W8 in many regard. There were already some rumors (+ non-denial from MS) that WP8 may not run WP7.5 code so this seems a strong indication that it will be more like W8.

And that's not a bad thing. I love C#/.Net (one of my projects, Tagxedo, was built with Silverlight), but given Microsoft doesn't have even the slightess will to push it, we may as well move on, or find some way to ride Mono. C++ is currently on my mind since it covers all ground (sans UI, which you still have to do anyway), probably in a way more straight-forward than Mono.

Lack of C++ code is a significant limitation for high end mobile games- both from performance and porting costs. MS absolutely knows this (and hears it regularly from game dev houses). Dunno if it'll be solved in WP8, but they have something in the works.

Derived from Win8 != WinRT- could just be the kernel and not app model.